Unit 5 Flashcards
(12 cards)
When a sample of water freezes, do the water molecules become motionless?
No, the water molecules lose their rotational and transnational movement but keep their vibrational movement. Only at 0 kelvins will it be motionless theoretically.
How does temp. affect pressure and volume (reference the combined laws)?
As temperature goes up, so does volume based on Charles’ law.
As temperature goes up, so does pressure based on Gay-lussac’s law.
How are gases affected by temperature?
According to kinetic molecular theory, lower temperatures result in less kinetic energy. less kinetic energy means that the molecules collide with their container less resulting in a reduced volume
Why is molar volume at SATP greater than molar volume at STP?
SATP molar volume is greater than STP due to the major difference, temperature. Higher temperature means higher volume and since the pressures are relatively fixed, one mole of gas will have a larger volume.
Characteristics of an ideal gas?
- Have high translational energy
- When entities collide, no kinetic energy is lost
- No attractive forces
- Do not condense into liquids when cooled
- Volume of an ideal gas entity is zero compared to it’s container
Why do you think the molar volume of helium is higher than the molar volume of the other real gases?
Helium has weak attractive forces which results in a greater molar volume. Attractive forces pull entities in a gas together which allows it to occupy less space
Difference between molar mass and molar volume?
Molar mass: How much a mole weighs depending on the type of atoms that make up the gas
Molar volume: How much one mole occupies depending on temperature and pressure
What is the purpose of kelvin units?
The kelvin unit scale allows for zero kinetic energy to equal zero units of temperature.
What is Dalton’s Law of Partial Pressures and why does water vapour increase with temperature?
Law: total pressure of non-reacting gases equals adding them up
Higher temperature means more evaporated molecules
Why does volume ratio work?
Volume ratio works because the volume is determined by the moles of gas present.
What are conditions (T and P) where gases deviate from ideal behaviour?
At high pressures and low temperatures, attractive forces between entities become significant which deviates from the ideal behaviour.
What is Kinetic Molecular Theory?
Kinetic Molecular Theory (KMT) describes how individual entities move (translational, rotational, and vibrational). Used to explain the behaviour of gases.
